Skeletal structures are comprised of bone, i.e., mineralized osseous tissue, and adjoining structures which include cartilage, among other elements. The spinal column is a highly complex skeletal structure which houses and protects critical elements of the nervous system. Although the spinal column is elaborate, it is a highly flexible structure capable of a wide range of motion. The human spine is composed of thirty-three vertebrae and their adjoining structures. Twenty-four of the thirty-six vertebrae are distinct bones capable of individual movement which are connected via facet joints. Facet joints allow the spine to move in every direction and maintain its flexibility. However, various diseases such as arthritis, degenerative disc disease, developmental abnormalities, trauma, chronic stress, and tumors, can result in spinal or facet pathologies which limit a patient's range of motion. Accordingly, the spine may require artificial support or stabilization at some point in a patient's life. One method of stabilizing the spine is by fusing facet joints. Facet joint fusion can reduce or eliminate pain and complications associated with degenerating facet joints.
While known devices for facet fusion are effective in certain applications, there remains a need for facet joint implants that do not require large incisions for implantation, relieve localized stress on adjacent vertebral end-plates, and can prevent migration and retropulsion within the spinal column.